The invention relates to a blast attenuator and particularly, but not exclusively, to a blast attenuator for a seat, blast floor or V-shaped hull of a vehicle used in a combat zone.
In a combat zone, vehicles such as tanks, personnel carriers including armored personnel carriers, trucks, and the like, may be targets of explosive devices, such as land mines, rocket propelled grenades and other improvised explosive devices (IEDs). Such explosive devices are typically triggered automatically by mobile trigger or the weight of the vehicle passing over the device and can cause catastrophic damage to both the vehicle and its occupants.
It is desirable to protect combat vehicles and their occupants from such explosive devices. For example, vehicles may be equipped with armor plating (for example, an armor-plated V-hull) to prevent blasts from penetrating the internal space of the vehicle. Nevertheless, while armor can prevent injury from shrapnel, occupants may be injured by the initial impact of the blast which violently displaces the vehicle and the subsequent “slam-down” as the vehicle returns to the ground.
It is known to provide combat vehicles with devices, such as blast attenuators, that absorb the impact of a blast and the subsequent slam-down in order to reduce the forces experienced by the occupants of the vehicle. For example, the seats of the vehicle may be connected to the body of the vehicle via a blast attenuator which allows the seat to move relative to the vehicle in the event of a blast, thus isolating the occupant from the vehicle.
A deformable link may be disposed between the seat and the vehicle to act as a blast attenuator. The deformable link is connected at one end to the seat and at the other end to a surface of the vehicle such as the floor or a wall. In the event of a blast, the link may deform so as to reduce the distance between its ends, thereby absorbing some of the impact of the blast. Similar functionality may be obtained with gas struts or oil-filled oleo struts.
However, such blast attenuators normally only provide attenuation of movement in a single direction (typically in the vertical direction). Moreover, the arresting load (or attenuating force) provided by such blast attenuators is not constant and varies depending on the applied blast load magnitude and the speed and acceleration of compression.
It is therefore desirable to provide an improved blast attenuator which overcomes some or all of the problems displayed by conventional blast attenuators.